Chapters 1 and 2
The Copernican Revolution, by Thomas Kuhn, is by now quite an old book, but it gives a wonderful sense of how people standing on the surface of the earth, looking at points of light in the sky, could move from that position to the understanding that the earth was the same kind of thing.
Darwin: A life in Science, by Michael White and John Gribbin, one of many biographies of Darwin, also contains a fascinating account of the surprisingly long history of pre-Darwinian speculations about evolution.
Created from Animals: The Moral Implications of Darwinism, by James Rachels, is an excellent, well argued and accessible introduction to Darwinism and philosophy, dealing with religion, animals and ethics in general.
Darwin's Dangerous Idea, by Daniel Dennett, another philosophical introduction to Darwinian matters, is extensively trailed in this book, and needs little further introduction. Dennett is in the thick of Darwinian controversy and therefore has his opponents, but even they would probably admit that the book was a real tour de force, with a wonderful scientific and philosophical sweep.
Evidence and Enquiry: Towards Reconstruction in Epistemology, by Susan Haack, is a recent analysis of questions about knowledge and evidence. It is serious philosophy - not a light read - but a first-rate study of some of the questions introduced in Chapter 2.
The Flamingo's Smile: Reflections in Natural History, in which the essay on Gosse appears, is one of Stephen Jay Gould's many collections of essays on Darwinian and related matters. Gould is one of the best-known combatants in the Darwin wars, but even people who disagree with many of his views would probably agree that his essays are delightful reading and full of interest. Ideal bedtime reading for newcomers to this terrain.
Chapters 3 and 4
The Moral Animal, by Robert Wright, is an immensely good read and an excellent popular introduction to evolutionary psychology.
The Red Queen: Sex and the Evolution of Human Nature, by Matt Ridley, is also very good. It is quite difficult in the first half, but becomes easier later, and connects well with the material of Chapter 3.